Metabolic fingerprinting of hard and semi-hard natural cheeses using gas chromatography with flame ionization detector for practical sensory prediction modeling

Metabolic fingerprinting using gas chromatography with flame ionization detector (GC/FID) was used to generate a practical metabolomics-based tool for quality evaluation of natural cheese. Hydrophilic low molecular weight components, relating to sensory characteristics, including amino acids, fatty acids, amines, organic acids, and saccharides, were extracted and derivatized prior to the analysis. Data on 12 cheeses, six Cheddar cheeses and six Gouda cheeses, were analyzed by multivariate analysis. Prediction models for two sensory attributes relating to maturation, "Rich flavor" and "Sour flavor", were constructed with 4199 data points from GC/FID, and excellent predictability was validated. Chromatograms from GC/FID and gas chromatography/time-of-flight-mass spectrometry (GC/TOF-MS) were comparable when the same column was used. Although GC/FID alone cannot identify peaks, the mutually complementary relationship between GC/FID and GC/MS does allow peak identification. Compounds contributing significantly to the sensory predictive models included lactose, succinic acid, l-lactic acid, and aspartic acid for "Rich flavor", and?lactose, l-lactic acid, and succinic acid for "Sour flavor". Since similar model precision was obtained using GC/FID and GC/TOF-MS, metabolic fingerprinting using GC/FID, which is a relatively inexpensive instrument compared with GC/MS, is easy to maintain and operate, and is a valid alternative when metabolomics (especially using GC/MS) is to be used in a practical setting as a novel quality evaluation tool for manufacturing processes or final products.     

Stress distributions in an elastic body due to molecular interactions considering one-dimensional periodic material distribution based on Mindlin’s solution

A method to calculate the stress distributions in a semi-infinite elastic body caused by molecular interactions has been established based on Mindlin’s solution. A molecular interaction force derived from the Lennard-Jones potential considering a one-dimensional periodic material distribution in the in-plane direction, i.e., x-direction, was used as a concentrated force in Mindlin’s solution. The stresses acting on the (100) and (001) surfaces (σ_x, σ_z, and τ_zx) for the distribution of two materials were calculated as a typical example of a periodic material distribution. The stress distributions were shown by color maps and the basic characteristics of the stress distribution, especially the effects of the surface distance, were quantitatively clarified. The asymptotic values of σ_x, σ_z, and τ_zx at the position far from the surface were analytically derived. Those of σ_x and σ_z had the same value, depending on the surface distance, while that of τ_zx was always zero. This difference comes from the existence of a non-fluctuation contribution.

     

Mixed Electronic-Ionic Conduction in Ru-Doped SrTiO3 at High Temperature

The electronic and ionic conduction behavior of Ru-doped SrTiO₃ at high temperature was investigated. The conductivity increased significantly with increasing Ru content. SrTi_0.80Ru_0.20O_3– exhibits fairly high conductivities, e.g., 3 S cm^–1 at 1000°C, and 2 S cm^–1 at 600°C. The conductivity had only a slight dependence on the partial pressure of oxygen over a wide range and was largely attributed to n-type electronic conduction. Ru-doped SrTiO₃ showed mixed oxide-ionic and electronic conduction under reducing atmospheres. The mechanism of the electronic and ionic conduction is discussed.     

Simple and Rapid Synthesis of Magnetite/Hydroxyapatite Composites for Hyperthermia Treatments via a Mechanochemical Route

This paper presents a simple method for the rapid synthesis of magnetite/hydroxyapatite composite particles. In this method, superparamagnetic magnetite nanoparticles are first synthesized by coprecipitation using ferrous chloride and ferric chloride. Immediately following the synthesis, carbonate-substituted (B-type) hydroxyapatite particles are mechanochemically synthesized by wet milling dicalcium phosphate dihydrate and calcium carbonate in a dispersed suspension of magnetite nanoparticles, during which the magnetite nanoparticles are incorporated into the hydroxyapatite matrix. We observed that the resultant magnetite/hydroxyapatite composites possessed a homogeneous dispersion of magnetite nanoparticles, characterized by an absence of large aggregates. When this material was subjected to an alternating magnetic field, the heat generated increased with increasing magnetite concentration. For a magnetite concentration of 30 mass%, a temperature increase greater than 20 K was achieved in less than 50 s. These results suggest that our composites exhibit good hyperthermia properties and are promising candidates for hyperthermia treatments.     

Annealing behavior of neutron irradiated β-SiC

The post-irradiation annealing behavior of β-SiC for use as a monitor of irradiation temperature is discussed. Powder and rods of polycrystalline β-SiC were irradiated to $\text{1.5 × 10}{}^{17}$ to $\text{5.0 × 10}{}^{19}\text{n/cm}{}^2\text{(E > 0.18 MeV)}$ at temperatures between 290 and 500°C. The estimated temperatures deduced from the changes in lattice constant and specific electric resistivity during progressive annealing, and from thermal expansion measurement by high-temperature X-ray diffraction agreed with values determined by means of a thermocouple. Thermal expansion measurement in a conventional dilatometer resulted in an over estimate of the irradiation temperature, and further improvement of this method is required for experimental application.     

Normal grain growth in porous and dense compacts

A rate equation of grain growth and a distribution function of grain radii were derived from the statistical viewpoint. The derived equation and function were successfully applied to the analysis of both the grain growth and grain radius distribution data in Cr-doped MgO. The diffusion coefficients of this sample were 10³ times larger than the oxygen self-diffusion coefficients in pure MgO.     

Solubility and Diffusion of Si in B4C

Diffusion couples of B₄C/SiC single crystals were annealed at 1800° to 2100°C. Electron probe tnicroanalysis of the joined diffusion couple showed that the solubility limit and diffusion coefficient, D, for Si in B₄C are 0.27 to 0.36% wt% and D = 0.165 exp(—101200/RT), respectively.     

Regulation by long-chain fatty acids of the expression of cholesteryl ester transfer protein in HepG2 cells

Cholesteryl ester transfer protein (CETP) is an important determinant of lipoprotein function, especially high density lipoprotein (HDL) metabolism, and contributes to the regulation of plasma HDL levels. Since saturated and polyunsaturated fatty acids (FA) appear to influence the CETP activity differently, we decided to investigate the effects of FA on the expression of CETP mRNA in HepG2 cells using an RNA blot hybridization analysis. Long-chain FA (>18 carbons) at a 0.5 mM concentration were added to the medium and incubated with cells for 48 h at 37°C under 5% CO₂. After treatment with 0.5 mM arachidonic (AA), eicosapentaenoic (EPA), and docosahexaenoic acid (DHA), the levels of CETP mRNA were less than 50% of the control levels (AA, P=0.0005; EPA, P<0.01; DHA, P<0.0001), with a corresponding significant decrease in the CETP mass. These results suggest that FA regulate the gene expression of CETP in HepG2 and this effect is dependent upon the degree of unsaturation of the acyl carbon chain in FA.     

Ni-Fe bimetallic anode as an active anode for intermediate temperature SOFC using LaGaO3 based electrolyte film

Effects of additives to Ni anode were studied and it was found that the anodic overpotential can be suppressed by addition of Fe. La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ (LSGM) film was deposited on the dense anode substrate consisting of NiO(Fe₃O₄)-Sm doped CeO₂. After in-situ reduction of NiO and Fe₃O₄ in the dense substrate, the substrate turned to be porous, however, change in size was not large by mixing with SDC. As a result, LSGM dense film with few micrometer thickness was successfully obtained on the porous Ni based anode substrate. By optimizing the thickness of the LSGM film and application of SDC interlayer, the high power density of SOFC single cell using LSGM/SDC bi-layer film as electrolyte at decreased temperature was fabricated and the electrical power generating property was measured as a function of temperature. The high maximum power density could be achieved to a value of 2 W/cm² at 873 K. Even at 673 K, the maximum power density of ca. 80 mW/cm² is exhibited and this high power density was a result of the low electrolyte resistance and the small anodic overpotential of Ni-Fe bimetallic anode.